Kaplan Ochm Notes.

The strain in cyclic molecules comes from angle strain

(created by stretching or compressing angles from their normal size)

torsional strain

(from eclipsing conformations),

nonbonded strain

(from interactions between substituents attached to nonadjacent carbons).

(Conclus.) Larger alkanes use the Greek root for the number ?

(pentane, hexane, heptane, octane, and so on).

Substituents attached to cyclohexane can be classified as axial

(sticking up or down from the plane of the molecule) Axial substituents create more nonbonded strain.

In anti staggered molecules

-two largest groups are 180º apart -strain is minimized

List the steps of IUPAC nomenclature: 1. 2. 3. 4. 5.

1. Find the longest carbon chain in the compound with the highest-order functional group; 2. Number the chain; 3. Name the substituents; 4. Assign a number to each substituent; 5. Complete the name

The International Union of Pure and Applied Chemistry (IUPAC) has designated standards for naming chemical compounds. There are five steps in the process which are?

1. find the longest carbon chain in the compound that contains the highest-priority functional group. This is called the parent chain. 2. number the chain in such a way that the highest-priority functional group receives the lowest possible number. This group will determine the suffix of the molecule. 3. name the substituents with a prefix. Multiple substituents of a single type receive another prefix denoting how many are present (di-, tri-, tetra-, and so on). 4. assign a number to each of the substituents depending on the carbon to which it is bonded. 5. complete the name by alphabetizing the substituents and separating numbers from each other by commas and from words by hyphens.

Which of the following lists the correct common names for ethanal, methanal, and ethanol, respectively? (A) Acetaldehyde, formaldehyde, ethyl alcohol (B) Ethyl alcohol, propionaldehyde, isopropyl alcohol (C) Ethyl alcohol, formaldehyde, acetaldehyde (D) Isopropyl alcohol, ethyl alcohol, formaldehyde

A The common name of ethanal is acetaldehyde, the common name of methanal is formaldehyde, and the common name of ethanol is ethyl alcohol. Isopropyl alcohol is the common name of 2-propanol. Propionaldehyde is the common name of propanal.

What is the IUPAC name for the following structure? (insert image) (A) 2,5-dimethylheptane (B) 2-ethyl-5-methylhexane (C) 3,6-dimethylheptane (D) 5-ethyl-2-methylhexane

A The first task in naming a compound is identifying the longest carbon chain. In this case, the longest chain has seven carbons, so the parent alkane ends in -heptane. (B) and (D) can therefore be eliminated. Then, we must make sure that the carbons are numbered so that the substituents' position numbers are as small as possible. This compound has two methyl groups; minimizing their position numbers requires us to number the chain from right to left. These methyl groups are attached to carbons 2 and 5, so the correct IUPAC name is 2,5-dimethylheptane. (C) is incorrect because the position numbers of the substituents are not minimized.

What is the highest-priority functional group in this molecule?(insert image) (A) Anhydride (B) Carbonyl (C) Ketone (D) Alkyl chain

A This molecule features an anhydride. The only other groups are hydrocarbon chains, which will provide part of the name of the parent root. Keep in mind that when a carbonyl group is present with a leaving group, the larger functional group (carboxylic acid, anhydride, ester, amide) takes priority over the carbonyl group alone. This molecule is propanoic anhydride

Which of the two possibilities below correctly numbers the carbon backbone of this molecule? (insert image) (A) Numbering scheme 1 (B) Numbering scheme 2 (C) Numbering schemes 1 and 2 are equivalent and correct. (D) Numbering schemes 1 and 2 are equivalent and incorrect.

A This molecule is 3-ethyl-4-methylhexane, not 2,3-diethylpentane. When naming alkanes, one must locate the longest carbon chain (6 carbons rather than 5 carbons), and the numbering system should give the alkyl groups the lowest possible numbers.

Pyruvic acid, one of the end products of glycolysis, is commonly called acetylformic acid. Based on its common name, the structure of pyruvic acid must be: (Insert structures)

A We can use the name acetylformic acid to figure out what our functional groups are. The prefix acet- refers to a two-carbon unit with one carbon in a carbonyl group—think of acetic acid, acetic anhydride, or acetaldehyde. The carbonyl carbon is the point of attachment to another functional group. Formic acid is a single-carbon carboxylic acid. Therefore, acetylformic acid is an acetyl group directly attached to formic acid, as shown in (A). (B) shows acetic acid, or vinegar; (C) shows glucose; and (D) shows formic acid.

What is a meso compound?

A meso compound contains chiral centers but also has an internal plane of symmetry. This means that the molecule is overall achiral and will not rotate plane-polarized light.

What suffixes are used for aldehydes and ketones; how are carbonyl groups named as a substituent? Aldehyde suffix: substituent prefix: Ketone suffix: substituent prefix:

Aldehydes are referred to with the suffix -al, while ketones are given the suffix -one. Carbonyl groups of both aldehydes and ketones are labeled as oxo- substituents (ketones may also be called keto- substituents).

(Conclus.) Alkenes are named by substituting what for the suffix and numbering the double bond by its lower-numbered carbon. Alkynes substitute what with the same numbering.

Alkenes are named by substituting -ene for the suffix and Alkynes substitute -yne with the same numbering.

What is the difference between an aldehyde and a ketone? Aldehyde: Ketone:

An aldehyde has a carbonyl group at the end of the chain. A ketone has a carbonyl group somewhere in the middle of the carbon chain. Another way to think of this is that the carbonyl carbon of an aldehyde has at least one bond to a hydrogen atom, whereas the carbonyl carbon of a ketone is always bonded to two other carbons.

Heteroatoms are?

Atoms besides carbon and hydrogen, like oxygen, nitrogen, phosphorus, or halogens.

Which of the following are common names for carboxylic acid derivatives? I. Acetic anhydride II. Formic acid III. Methyl formate (A) I and II only (B) I and III only (C) II and III only (D) I, II, and III

B Acetic anhydride is the common name for ethanoic anhydride. Methyl formate is the common name for methyl methanoate; we can infer this from the common root form- and the ester suffix -oate (which is sometimes shortened to -ate for pronunciation purposes). Formic acid is the common name for methanoic acid, but this is a carboxylic acid—not a derivative.

The common names for the aldehydes and carboxylic acids that contain only one carbon start with which prefix? (A) Para- (B) Form- (C) Meth- (D) Acet-

B Form- is a prefix shared by the common names of methanoic acid (formic acid) and methanal (formaldehyde)

What is the proper structure for 2,3-dihydroxybutanedioic acid (tartaric acid)? (insert image)

B We know from the IUPAC name that we have a butanedioic acid backbone—in other words, a four-carbon backbone with carboxylic acids at either end. Adding the hydroxyl groups at carbons 2 and 3 then yields the correct structure.

The IUPAC name for the following structure starts with what prefix? ( insert image). (A) 3-methyl- (B) 2-methyl- (C) 2-hydroxy- (D) 3-hydroxy-

B We know right away that (C) and (D) will be incorrect because a hydroxyl group is of higher priority than a methyl group. We also know that we will number the carbon chain so that the hydroxyl group receives the lowest possible position. Therefore, this molecule is 2-methyl-2-butanol, which starts with the prefix 2-methyl.

Fill in the correct names for the alkanes listed below. If more than one compound can be described with a given molecular formula, name the straight-chain alkane to which the formula refers and draw one alternative. Molecular FormulaL IUPAC Name (Straight-Chain Alkane): Alternative Structure CH4 : Methane: No alternative structures. C2H6: Ethane: No alternative structures. C3H8: Propane: No alternative structures C4H10: Butane: see below C5H12: Pentane: see below C6H14: Hexane: see below C7H16 Heptane: see below C8H18 Octane: see below C9H20 Nonane: see below C10H22: Decane: see below

Butane and all hydrocarbons that are larger than butane may have a branched appearance, which shortens the parent chain. An example is isobutane, properly named methylpropane, shown here. Any branched hydrocarbon with the correct number of carbons and no multiple bonds or rings is correct.

Which of the following are considered terminal functional groups? I. Aldehydes II. Ketones III.Carboxylic acids (A) I only (B) III only (C) I and III only (D) I, II, and III

C Aldehydes and carboxylic acids are characterized by their positions at the ends of carbon backbones and are thus considered terminal groups. As a result, the carbons to which they are attached are usually designated carbon 1. Ketones are internal by definition because there must be a carbon on either side of the carbonyl.

The IUPAC name for the following structure ends in what suffix? (image) (A) -ol (B) -one (C) -oic acid (D) -yne

C Among the functional groups presented, carboxylic acids have the highest priority, and their compounds end with an -oic acidsuffix.

Consider the name 2,3-diethylpentane. Based on the structure implied by this name, the correct IUPAC name for this molecule is: (A) 2,3-diethylpentane. (B) 1,2-diethylbutane. (C) 3-ethyl-4-methylhexane. (D) 3-methyl-4-ethylhexane.

C Draw out the molecule, and you will see that the longest carbon chain with the substituents at the lowest possible carbon numbers is actually different from the one chosen in the original name. The correct IUPAC name for this molecule is 3-ethyl-4-methylhexane.

If all prefixes were dropped, what would be the name of the parent root of this molecule? (insert image) (A) Propanoate (B) Propanol (C)Propanoic acid (D) Propanoic anhydride

C The highest-priority functional group in this molecule is the carboxyl group, so this will be a component of the backbone and provides the suffix of the molecule. This molecule is 2-methyl-3-oxopropanoic acid.

NADH is a coenzyme that releases high-energy electrons into the electron transport chain. It is known as nicotinamide adenine dinucleotide or diphosphopyridine nucleotide. What functional groups exist in this molecule? I. Phosphate II. Amide III. Anhydride (A) I only (B) II only (C) I and II only (D) I, II, and III

C The suffix -amide in nicotinamide indicates that this compound contains an amide functional group. The prefix diphospho- indicates that there are two phosphate groups as well. Even if we did not know the prefix phospho- from this chapter, we should recognize that nucleotides, mentioned in the name of the compound, contain a sugar, a phosphate group, and a nitrogenous base. The structure of NAD+, the oxidized form of NADH, is shown below.

What are chemical properties?

Chemical properties are aspects of a compound that change chemical composition; in organic chemistry, chemical properties are usually dictated by the reactivity of various functional groups.

What is the difference between a conformational and a configurational isomer? Conformational: Configurational:

Conformational isomers are stereoisomers with the same molecular connectivity at different points of rotation around a single bond. Configurational isomers are stereoisomers with differing molecular connectivity.

Of the compounds cyclopropanol, 2-propanol, acetone, and prop-2-ene-1-ol, which are structural isomers of each other?

Cyclopropanol, acetone, and prop-2-ene-1-ol are all structural isomers of each other with the chemical formula C3H6O. 2-Propanol has the chemical formula C3H8O.

What is the IUPAC name for the following structure? ( insert image) (A) 4-isopropyl-2-methylhexane (B) 3-isopropyl-5-methylhexane (C) 2,2,5-trimethyl-3-ethylhexane (D) 3-ethyl-2,2,5-trimethylhexane

D We begin by finding the longest carbon chain; because there are no non-alkyl groups, we don't need to worry about any other groups' priorities. We then number our carbons such that the lowest possible combination of numbers is given to the various substituents. Then substituents are organized alphabetically, not numerically—eliminating (C).

The function of the parent chain is ?

Determine the root of the name.

Is the following compound a geminal diol or a vicinal diol? (include structure/ image later).(1.2 check)

Diols are alcohols with two hydroxyl groups. In a geminal diol, these hydroxyl groups are on the same carbon (geminiderives from the Latin for "paired, twins"). In a vicinal diol, the hydroxyls are in the vicinity of each other—on adjacent carbons (vicinus derives from the Latin for "neighbor"). Thus, the compound shown is a geminal diol.

Consider the six pairs that the following four molecules can make. Which pairs are enantiomers? Diastereomers?

Enantiomers are nonsuperimposable mirror images. That means the molecules must be mirror images that are different from one another (superimposable mirror images represent the same object). The molecules on the top-left and bottom-right are nonsuperimposable mirror images and therefore enantiomers. The same is true for the top-right and bottom-left. All other combinations are diastereomeric because the pairs differ at some, but not all, stereocenters.

Substituents are?

Functional groups that are not part of the parent chain.

Mnemonic: Vicinal diols are in the vicinity of each other, on adjacent carbons. Geminal diols—like the Gemini twins—are paired on the same carbon.

Helpful

Fill in the common names in the following chart. (1.3 check) IUPAC name : Common name Methanal: Ethanal: Propanal: Propanone:

IUPAC name with common name Methanal: Formaldehyde Ethanal: Acetaldehyde Propanal: Propionaldehyde Propanone: Acetone

What are the common names for 2-propanol and ethanol? 2-propanol: Ethanol:

Isopropyl alcohol and ethyl alcohol, respectively.

For a molecule with a double bond, an aldehyde, and an alcohol, which functional group would determine the suffix when naming?

Ketones and aldehydes both take precedence over both alcohols and hydrocarbon chains, and the functional group that is the highest priority determines the suffix. Because the aldehyde is chain-terminating and therefore on carbon number 1, the aldehyde would determine the suffix when naming this compound.

Physical properties?

No change in composition of matter; examples include melting point, boiling point, solubility, odor, color, density.

What are physical properties? Give three examples of physical properties.

Physical properties are aspects of a compound that do not play a role in changing chemical composition. Examples include melting point, boiling point, solubility, odor, color, and density.

How is priority assigned under the Cahn-Ingold-Prelog priority rules?

Priority is assigned by atomic number: the atom connected to the stereocenter or double-bonded carbon with the highest atomic number gets highest priority. If there is a tie, one works outward from the stereocenter or double-bonded carbon until the tie is broken.

Chemical properties?

Reactivity of molecule, resulting in change in composition; generally attributable to functional groups in the molecule.

What property or properties do structural isomers have in common?

Structural isomers share a molecular formula, and not necessarily anything else.

For each of the Fischer projection manipulations listed below, is stereochemistry retained or inverted? Switching a pair of substituents: Switching two pairs of substituents: Rotating the molecule 90°: Rotating the molecule 180°:

Switching a pair of substituents inverts stereochemistry; switching two pairs retains it. Rotating the molecule 90° inverts stereochemistry; rotating 180° retains it.

In a molecule with two double bonds adjacent to each other and an alcohol, which functional group would take precedence in naming?

The alcohol would take precedence because the carbon to which it is attached has a higher oxidation state.

(1.4 check) What would be the names of the ester, amide, and anhydride derivatives of pentanoic acid? Assume that the R group on the ester is -CH3 and that the amide is unsubstituted. Ester: Amide: Anhydride:

The ester derivative would be methyl pentanoate. The amide would be pentanamide. The anhydride would be pentanoic anhydride. 3-methyl-2-oxopentanoic acid

Name the following compound using E/Z nomenclature: (2.3)

The highest-priority functional group is an alkene, and the longest carbon chain that contains the double bond is five carbons long. So, the root will be pent- and the suffix will be -ene. There are three substituents: a chlorine and two methyls. Number the chain to give the double bond the lowest possible number, in this case from left to right. Bringing it all together gives 1-chloro-2,3-dimethyl-1-pentene. However, there are two possible configurations around the double bond. To determine (E)/(Z) designation, start by identifying the highest-priority substituents attached to each double-bonded carbon. The chlorine and butyl groups are the highest-priority substituents and are on opposite sides of the double bond (in addition to being on opposite ends of the double bond), so this molecule is (E)-1-chloro-2,3-dimethyl-1-pentene.

The primary goal of the International Union of Pure and Applied Chemistry (IUPAC) naming system is ?

To create an unambiguous relationship between the name and structure of a compound.

Conformational isomers

differ by rotation around a single (σ) bond.

(Conclus.) Alkenes and alkynes contain what bonds, respectively?

double and triple bonds, respectively.

How do you know what the highest-priority functional group is?

has the most oxidized carbon.

Staggered conformations .

have groups 60° apart, as seen in a Newman projection.

Eclipsed conformations

have groups directly in front of each other as seen in a Newman projection.

(2.2) Complete the Newman projection for the following compound:

image

(Conclusion slide )The first four alkanes are ?

methane (CH4), ethane (C2H6), propane (C3H8), and butane (C4H10).

(Conclus). Alcohols contain a hydroxyl (-OH) group, which substitutes for ?

one or more of the hydrogens in the hydrocarbon chain.

The Longest Carbon Chain Containing the Highest-Order Functional Group also known as?

parent chain

Structural isomers

share only a molecular formula. They have different physical and chemical properties.

In gauche staggered molecules

the two largest groups are 60° apart.

In totally eclipsed conformations,

the two largest groups are directly in front of each other and strain is maximized.

Cyclic molecules

usually adopt nonplanar shapes to minimize this strain.